wfs: Fix error when parsing empty OtherCRS

[bierik]

According to the official XSD, <OtherCRS /> and <OtherSRS /> are valid for WFS capabilities.
Previously, the Crs tried to split the id, which may be None in this case and resulted in an error.
With this change, both wfs110 and wfs200 reject None values entirely.

[geographika]

Thanks @bierik for the fix and test.

From https://schemas.opengis.net/wfs/2.0/wfs.xsd:

<xsd:element name="OtherCRS" type="xsd:anyURI" minOccurs="0" maxOccurs="unbounded"/>

I assume xsd:anyURI allows an empty string so this seems good to me (although the server omitting it would be more logicial).

I presume you ran into this in a real-world use-case. Do you know which server produced the GetCapabilities response?

[bierik]

@geographika As far as I can tell, xsd:anyURI allows an empty string, which is parsed as None by lxml. I validated the response from the capabilities endpoint that I was having trouble with against the XSD you pointed out, and it turned out to be completely valid.

Unfortunately, the services that produced this response are internal services from the customer. I completely agree with you that these services should omit the empty tags. But for me, it was just easier to fix it in the client library 😄. And if the XSD allows it, the client should handle it, right?